#define _CRT_SECURE_NO_WARNINGS 1
#include<stdio.h>
#include<stdlib.h>
#include<string.h>

int main()
{
	char* result = (char*)malloc(sizeof(char) * 100);
	scanf("%s", result);
	int len = strlen(result);
	int count = 0;
	for (int i = 0; i < len; i++)
	{
		int repeat = 0;
		if (result[i] <= '~' && result[i] >= 0)
		{
			for (int j = 0; j < i; j++)
			{
				if (result[i] == result[j])
				{
					repeat = 1;
					break;
				}
			}
			if (repeat == 0)
			{
				count++;
			}
		}
			
	}
	printf("%d", count);
	return 0;
}